Transport Across Cell Membranes

Question 1

Cell membranes are selectively permeable what does this mean?

Answer 1

This means it only allows some molecules to pass not others

Question 2

What are the two substances cell membranes are composed of?

Answer 2

1. Phospholipids
   2.proteins

Question 3

What is a concentration gradient?

Answer 3

Different concentrations of substances exist between cells and their environment.

This is the difference in concentration between two substances.

Question 4

Diffusion def

Answer 4

The movement of molecules down a concentration gradient from a high to low concentration

Question 5

Examples of diffusion

Answer 5

-Oxygen
-carbon dioxide

Question 6

Osmosis def

Answer 6

The movement of water molecules from a high water concentration to a low water concentration through a selectively permeable membrane

Question 7

Examples of osmosis

Answer 7

-water

Question 8

Active transport def

Answer 8

The movement of molecules against the concentration gradient from a low concentration to a high concentration. Active transport requires energy and proteins

Question 9

Examples of active transport

Answer 9

Glucose

Question 10

What transport are active/passive

Answer 10

Diffusion and osmosis-passive
Active transport-active

Question 11

What transports require energy

Answer 11

Diffusion and osmosis -no
Active transport -yes

Question 12

What ways do the molecules move in each transport

Answer 12

Diffusion and osmosis -down
Active transport -against

Question 13

What does an animal cell do in high water?

Answer 13

Burst

Question 14

What does a plant cell do in high water

Answer 14

Becomes turgid

Question 15

What does an animal and plant cell do in equal solution

Answer 15

Stays the same

Question 16

What does an animal cell do in low water

Answer 16

Shrinks

Question 17

What does a plant cell do in low water

Answer 17

Becomes plasmolysed